Black screen, no USB working, fans running

Setup:

MOBO: ASRock A320M Pro4 Micro ATX

CPU: AMD Ryzen 3 1200 quad-core

Memory: 16 GB G.Skill Aegis DDR4-2133

GPU: MSI GTX 1050TI 4GB (dual fan)

HDD: Toshiba 500GB 3.5" 7.2k RPM SATA

PSU: Corsair CX450 450W 80+

OS: Windows 10 Home

So starting about a month ago and becoming more frequent, I've been having my computer screen go black (says it doesn't have a signal, doesn't reconnect when I disconnect/reconnect to the GPU or switch it to MOBO output), keyboard and mouse stop working (both USB), USB bluetooth stops working, USB mic stops working, and ethernet light stops flashing. The computer seems to stay on, as the fans keep running and the power light stays on, not blinking (which it usually does while asleep). The fans will run for at least 24 hours, and only turn off when I hard boot the computer or remove power.

It originally only happened when I was playing games, which was likely because I use another computer for most work and only use this computer for gaming. This week, when I started spending more time on the computer to diagnose the problem it started getting these crashes during normal operation, even sometimes with no applications running. By yesterday, the crashes became so frequent that I had difficulty getting through boot and login to even see my desktop. When I did get to my desktop, it would crash within 1-2 minutes.

Earlier this week (before the computer became inoperable), I tried testing out some of the components to see if I could find the problem. I thought the GPU could be overheating and causing the black screen, so I monitored heat while running some high graphics games and never saw a temp over 55C. While running through event files I noticed automatic system diagnostics which had supposedly found the HDD and CPU were working fine (at least at the time of the diagnostic). I didn't find any event files which could explain the crashes themselves, although some warning said there was low memory. The HDD is several years old, but has 300+ GB free memory as of right now. I got the HDD in September from a friend who said he's never had problems with it. It was formatted in September when I put it in this PC. All the other parts are new.

Any ideas on what might be causing the problem? Any help is appreciated.